Liver Disease

What is liver disease and liver failure?

The liver is one of the most important organs in the horse's body. It weighs approximately 5kg and is located centrally within the abdomen. The liver is involved in many essential biological processes, therefore advanced disease where 60-75% of the liver is damaged can be life threatening and will need careful long term management including suitable dietary management. However, under most circumstances the liver can regenerate therefore clinical signs may not always be obvious although athletic performance may be affected.

Ragwort poisoning is thought to be the most common cause of liver disease in horses. Although ragwort is most commonly consumed by horses turned out on very sparse pasture, it is much more palatable when dried in hay. Ragwort contains pyrrolizidine alkaloids, which are naturally occurring chemical compounds, which destroy the liver and stop the liver from regenerating.

Until recently nutritional management of horses and ponies with liver disease has focused on providing a low protein, low oil and often a high starch diet. However as knowledge of liver disease in horses and other species improves, there appears to be little justification for such dramatic adjustments. In fact, dietary adaption is no longer recommended at all in cases of 'compensated' liver disease unless the current diet is significantly over-supplied with protein and/or starch. The following recommendations only relate to horses with severe liver disease showing signs such as weight loss, jaundice and depression or abnormal blood results such as low serum albumin.

Aim to meet but not exceed protein requirements. Excessive protein intake may be most detrimental in horses/ ponies displaying neurological signs of liver disease such as head pressing. However encouraging individuals to eat may be more important than restricting protein intake

Providing sufficient levels of quality protein and in particular lysine is still important

Although high protein ingredients/ feeds such linseed and soya do not need to be avoided completely, seek advice from a nutritionist before adding them to your horse's diet

Regulating protein intake is thought to be less important for horses showing other clinical signs of impaired liver function

Excessively restricting protein intake may lead to the breakdown of lean tissue

Starch intake should be restricted to a maximum of 1g/ kg bodyweight per meal i.e. 500g for a 500kg horse. However other individual requirements may warrant further restriction of starch i.e. those prone to laminitis

High starch diets may lead to insulin dysfunction which in turn may exacerbate any insulin resistance associated with liver failure

Divide compound feeds into small, frequent meals (a minimum of 4 but 4-6 ideally) to help maintain blood glucose levels and prevent the breakdown of amino acids in the liver

Oil can be fed at 0.1-1ml/ kg bodyweight per day in the total diet i.e. 50-500mls per day for a 500kg horse provided there are no signs of malabsorption such as diarrhoea or steatorrhea (fat in the faeces) or other contraindications advised by your vet. Any oil should be introduced gradually, adjusting the quantity fed according to the horse's energy requirements.